Adequate treatment and disposal of human waste is essential to preserve public health. Failure to properly treat and dispose of human waste results in a heightened risk of disease outbreaks, such as from cholera and bacterial agents. In addition, improper waste disposal often results in environmental degradation as water sources are loaded with excess nutrients. This excess nutrient loading can result in elevated nitrate levels in aquifers, unattractive algae blooms in lakes and rivers, and anoxic conditions developing in surface waters as algae blooms die and decay.
In modern urban areas sewer and water treatment occurs at centralized sewer treatment facilities equipped to properly handle large levels of waste. In rural areas not serviced by sewer systems, a method of disposal of common household and human wastes is necessary. For these rural areas an anaerobic treatment process known as a septic system is often employed. In most septic systems the treatment process consists of a series of typical steps: a septic tank collects the wastes from the house, biological processes occur in the septic tank that result in converting solids to liquids, an absorption field is dosed with effluent from the septic tank that is deposited into the soil from pipes with holes, and finally the absorption field soil converts the waste water to clean water.
Locating and designing a septic system in an area with suitable soil is critical to providing adequate on site sewage treatment. Soil that is too coarse will not adequately remove nutrients and bacteria. Loam or clay loam soils can do an excellent job of nutrient and bacteria removal but require a relatively large soil treatment area.
Therefore, the soil absorption rate is a critical element of proper septic placement, sizing, and construction. If the absorption rate is too slow it will cause the sewage to back up into the house or move over the surface of the soil. If the absorption rate is too fast, it will allow insufficient time for microbes in the soil to clean the water. Also, if space is limited or soil conditions are poor, homeowners may need a modified treatment system.
In order to measure soil absorption, a percolation test is performed to calculate perc rate by measuring the time it takes water to drop a predetermined amount in a pre-wetted hole, typically time divided by drop in water level, often expressed as minutes per inch of water level drop. However, existing equipment for measuring the perc rate is inadequate in numerous regards: it is cumbersome to use, can be imprecise, and is very time consuming to properly operate. Typical equipment in use today involves, for example, manual operation of floats, measuring sticks and a timing device to determine perc rate. Typically, a technician must stay with the rudimentary test equipment to collect and analyze readings for a multi-hour period.
Modifications have been made in some percolation test equipment, such as that disclosed in U.S. Pat. No. 7,062,957 to inventor Martin Power. One of the problems with the Power design is that it is cumbersome, typically requiring creation of a large hole for the perc testing equipment (necessitating large amounts of water for the perc test and a greater impact on test area from the larger hole or holes) and lowering of a screen into the hole to stabilize the opening. The large hole can be dug, for example, using a truck-mounted backhoe that is heavy, hard to maneuver in small spaces, and expensive. Also, the Power method lowers a sensor into a hole to measure the level of water in the hole. Clearly the Power method has significant limitations, due to the overall design and the manner in which level measurements are made.
Therefore, a need exists for improved perc test equipment that allows fast, accurate, efficient perc testing.